Inductive coupling is an effect used to transfer electrical energy from one circuit to an adjacent circuit through inductive coils. A variable current on a primary coil is used to create a varying magnetic field, and thus a voltage, in a secondary coil. Wireless charging systems employing inductive coupling are useful for transferring energy from one device to another. Such systems are used for supplying power, charging batteries, and in some cases also for transferring data. Challenges inherent in such systems include providing efficiency in transferring signals. Inefficient systems generate excess heat and are limited in their maximum signal transfer capability. Existing systems accomplish signal transfer by exciting a primary side coil and receiving with a secondary side coil within a given frequency and amplitude range. Typically, the maximum signal amplitude that can be transferred is limited by the primary side driver amplitude and frequency as well as the inductance of the coils and the coupling between coils. Typically, any given signal transfer coil is only optimized for a small range of signal amplitude transfer levels. Operating the coils outside this narrow range tends to result in reduced efficiency and/or reduced coupling between coils.
Due to these and other problems and potential problems, improved coupled inductor systems would be useful and advantageous contributions to the arts. In particular, systems capable of supporting a wide range of amplitude transfer levels, e.g., milliWatts to 100's of Watts, from a single primary and/or secondary side hardware unit would be highly useful.